Biomedical subjects

A Oldfors

Publications and source records attributed to A Oldfors.

At least 73 records · Page 4Linked to original sources

PubMed1995

De novo mutation in the mitochondrial ATP synthase subunit 6 gene (T8993G) with rapid segregation resulting in Leigh syndrome in the offspring.

The mutation in the mitochondrial ATP synthase subunit 6 gene (ATP6 T8993G) was identified in a male infant who died at age 15 months of Leigh syndrome. He had 94% mutated mitochondrial DNA (mtDNA) in muscle and 92% in lymphocytes. His mother was healthy but had 37% mutated mtDNA in muscle and 38% in lymphocytes. The proband's brother, who was also healthy, had 44% mutated mtDNA in lymphocytes. No mutated mtDNA was detected in muscle and lymphocytes from the maternal grandmother of the proband or in lymphocytes from 15 other maternal relatives, showing that the first carrier of the ATP6 T8993G mutation in this family was the mother of the proband. This study shows that this point mutation may occur at substantial levels in a carrier of a de novo mutation and rapid segregation with high levels of mutated mtDNA causing neurodegenerative disease may occur in the second generation.

2,4-Dinitrophenol↗

PubMed1995

Tissue distribution and disease manifestations of the tRNA(Lys) A-->G(8344) mitochondrial DNA mutation in a case of myoclonus epilepsy and ragged red fibres.

This man with myoclonus epilepsy and ragged red fibres (MERRF) syndrome due to the tRNA(Lys) A-->G(8344) mutation of mitochondrial DNA (mtDNA) died of bronchopneumonia at 18 years of age. He had progressive clinical symptoms from 6 months of age manifesting as ataxia, myoclonic seizures, and muscle weakness. A post-mortem examination revealed 91-99% mutated mtDNA in all 32 examined tissue samples, including various organs and different brain regions. The brain appeared without macroscopic changes, but microscopic examination showed degeneration with loss of nerve cells and gliosis affecting the globus pallidus, substantia nigra, red nucleus, dentate nucleus, inferior olivary nucleus, cerebellar cortex, and the spinal cord. Skeletal muscle showed cytochrome c oxidase deficient muscle fibres with proliferation of mitochondria. In addition to pathological changes of muscle and brain there were few morphological changes that could be attributed to his mitochondrial disease. These data support the concept that in patients with the tRNA(Lys) A-->G(8344) mutation who are manifesting disease there are high levels of mutated mtDNA in all tissues, but only some tissues and brain regions are vulnerable.

Adolescent↗

PubMed1995

Atypical presentation of multisystem disorders in two girls with mitochondrial DNA deletions.

UNLABELLED: We describe two girls with atypical presentations of multisystem disorders due to deletions in mitochondrial DNA (mtDNA). One presented with painful carpopedal spasms due to hypoparathyroidism at the age of 4 years. The disease was rapidly progressive with development of truncal and limb ataxia, spastic paraparesis, muscle weakness and wasting, pigmentary retinal degeneration and sensorineural hearing loss. She had short stature and vitiligo patches, hirsutism, anaemia, diabetes mellitus and exocrine pancreatic dysfunction. The other girl presented at the age of 6 years with polydipsia, polyuria and fatigue due to renal tubular dysfunction. The disease was insidiously progressive with poor growth and development of sensorineural hearing loss, muscle weakness and truncal and limb ataxia. Morphological, enzyme histochemical and biochemical investigations indicated mitochondrial dysfunction of skeletal muscle, liver and kidney in one patient and of skeletal muscle and liver in the other. Both patients had large proportions of mtDNA molecules with deletion in liver, kidney, skeletal muscle and blood cells. CONCLUSION: It may be concluded that symptoms from several different organs may be the first manifestation of a mtDNA deletion disorder.

Blotting, Southern↗

PubMed1995

Effects of nandrolone propionate on experimental tumor growth and cancer cachexia.

We studied the tumor host response to excessive doses of an anabolic steroid (nandrolone propionate, 2.5 mg 20 g intraperitoneally every second day for 11 days) with respect to body composition and tumor cell kinetics in MCG 101 sarcoma-bearing mice (C57BL/6J) with progressive cachexia. Although survival and food intake were not affected, a significant weight gain was observed that was essentially attributed to water retention. Net protein content was increased only to a minor extent (15%), of which only the liver accounted for a significant part of the body compartments. Hepatic protein accumulation was obviously caused by decreased protein degradation, since hepatic RNA content was unchanged. After anabolic steroid administration, reduced histochemical staining of succinate dehydrogenase was observed in skeletal muscles rich in oxidative type 1 fibers, but it was not different from that of tumor-bearing control animals, which was also confirmed by measurements of citrate synthase and cytochrome c oxidase activities in skeletal muscle and liver tissue. The anabolic steroid had no significant effect on tumor growth in terms of weight progression, energy state, polyamine synthesis rate, cell division rate, and cell cycle cytocompartments. We conclude that anabolic steroid supplementation is not therapeutically beneficial in counteracting progressive weight loss in experimental cancer.

Anabolic Agents↗

PubMed1995

Mitochondrial DNA deletions in muscle fibers in inclusion body myositis.

Inclusion body myositis (IBM) is an autoimmune, inflammatory myopathy where morphological changes of muscle, including ragged red fibers, have indicated mitochondrial dysfunction in some muscle fibers. In this study enzyme histochemical analysis showed that cytochrome c oxidase (COX)-deficient muscle fibers were present at a frequency ranging from 0.5 to 5% of the muscle fibers in a series of 20 IBM patients. In age-matched controls, only occasional COX-deficient muscle fibers were present. Polymerase chain reaction (PCR) analysis of DNA extracted from muscle tissue of the IBM patients showed multiple mtDNA deletions. PCR analysis of isolated, single muscle fibers showed presence of mtDNA with only one type of deletion and deficiency of wild-type mtDNA in each COX-deficient muscle fiber. This finding was supported by results from in situ hybridization using different mtDNA probes on consecutive sections. A 5 kb deletion was identified in all 20 IBM patients. DNA sequencing of the breakpoint region showed that this deletion was the so-called "common deletion." Most but not all of the investigated deletion breakpoints were flanked by direct repeats. COX-deficient fibers were more frequent among fibers with positive immunostaining with antibodies directed toward a regeneration marker, the Leu-19 antigen, than in the entire fiber population. These results show that COX deficiency in muscle fiber segments in IBM is associated with deletions of mtDNA. Clonal expansion of mtDNA with deletions may take place in regenerating muscle fibers following segmental necrosis.

Adult↗

PubMed1995

Local T-cell proliferation and differentiation in inflammatory myopathies.

Our objective was to investigate the patterns of proliferation and differentiation of infiltrating cells in inflammatory myopathies. Immunohistochemical staining was performed on muscle biopsy specimens from 18 patients with inclusion body myositis, polymyositis and dermatomyositis using monoclonal and polyclonal antibodies. An abundance of cells were TNF-alpha+ (4-8%), ICAM-1+ (7-65%), IFN-gamma+ (3-6%), and Ki-67+ (4-8%). It was shown that 70% of the Ki-67+ cells were Ki-67+CD3+ cells. Very few mononuclear cells were IL-2R+. MHC-I expression was found on nearly all muscle fibres in all cases, while MHC-II expression was found on occasional muscle fibres in 1/3 of cases. Analysis of repeated biopsies from four IBM patients after prednisolone treatment showed no change in the proportions of TNF-alpha, ICAM-1, IFN-gamma or Ki-67 positive cells. In inflammatory myopathies there is an intense proliferation and differentiation of inflammatory cells in situ, indicating a local stimulation of the inflammatory process.

Adult↗

PubMed1994

Rett syndrome: 3-D confocal microscopy of cortical pyramidal dendrites and afferents.

Autopsy material from three patients with Rett syndrome and six control cases (frontal, temporal and motor cortical areas) were studied. Pyramidal and non-pyramidal neurones, 100-200 in each specimen, were visualized by Lucifer Yellow microinjection. 3-D reconstructions and rotations were computed using the VoxelView/GT program. Various types of abnormalities in 3-D dendritic architecture of pyramidal neurones in different cortices were observed. Some pyramidal cells in layers II-III had a subnormal number of dendrites. The normally occurring specializations in pyramidal architecture in different cortical areas were absent. Decreased numbers and regional loss ('naked' areas) of dendritic spines were found. Widely distributed cortical afferents were shown by the carbocyanine dye (DiI) tracing method. PAD showed no microdysgenesis, in contrast to the observations in epilepsy.

Adolescent↗

PubMed1994

Low levels of mitochondrial transcription factor A in mitochondrial DNA depletion.

Low levels of mitochondrial transcription factor A (mtTFA) were found in muscle fibers with mitochondrial DNA (mtDNA) depletion in a child with fatal mitochondrial myopathy and also in a human cell line lacking mtDNA. High levels of this transcriptional activator were found in muscle fibers with mtDNA accumulation in two patients with single mtDNA deletions. This is the first example of a nuclear gene product that varies with the levels of mtDNA in humans. Since transcription is required for the replication of mtDNA, it is possible that mtTFA may be involved in the regulation of mtDNA replication.

Child, Preschool↗

PubMed1994

Automatic sequencing of mitochondrial tRNA genes in patients with mitochondrial encephalomyopathy.

We have investigated nine children with infantile onset of mitochondrial myopathy and two adults with myoclonus epilepsy and ragged-red fibers (MERRF) and chronic progressive external ophthalmoplegia (CPEO), respectively. These patients lacked any of the previously known pathogenic tRNA mutations. Southern blot analysis of muscle mtDNA revealed no deletions. The tRNA genes of muscle mtDNA were sequenced. Restriction enzyme analysis of PCR fragments was performed to verify the presence of the mutations identified by automatic sequencing. Several tRNA mutations were found, but they were all homoplasmic. Furthermore, the mutations were either present in controls or did not change nucleotides conserved between species. This strongly suggests that none of the tRNA mutations identified in the 11 patients with mitochondrial encephalomyopathy was pathogenic. It can thus be concluded that mitochondrial tRNA mutations and mtDNA deletions probably are an infrequent cause of mitochondrial disorders in infants. Patients with MERRF and CPEO may lack both pathogenic point mutations of tRNA genes and deletions of mtDNA.

Adult↗

PubMed1994

Restricted use of T cell receptor V genes in endomysial infiltrates of patients with inflammatory myopathies.

Inclusion body myositis (IBM), polymyositis (PM) and dermatomyositis (DM) are diseases characterized clinically by progressive muscle weakness and histologically by T lymphocyte infiltrates in striated muscle. The pathogenetic role of these cells is proposed to be cell-mediated cytotoxicity in PM and IBM, but the exact mechanisms of their action are poorly understood. Characterization of the variable regions of T cell receptors (TcR) on the infiltrating lymphocytes may be expected to provide insights into the mechanisms of local activation of the immune system in inflammatory myopathies. Immunohistochemical analysis using a panel of monoclonal antibodies specific for 11 V alpha/beta TcR was performed on cryosectioned muscle biopsy specimens from eight patients with IBM, eight with PM and three with DM. In addition, TcR expression was studied in inflammatory infiltrates in skin biopsies obtained from some of the IBM patients challenged locally with tuberculin. Flow cytometry was used to assess expression of TcR on peripheral blood lymphocytes. All the patients displayed a clear restriction of TcR usage, preferentially limited to V alpha 2 and V beta 3 TcR families in the endomysial, but not in perivascular infiltrates, even within the same muscle specimen. Such a restriction was not found in skin punch biopsies or PBL from the same subjects. Our results suggest that T cells extravasate non-selectively to the skeletal muscle, but once there, only certain TcR families proliferate, presumably after encounter with a locally exposed superantigen.

Gene Expression↗

PubMed1994

Duchenne muscular dystrophy and spinal muscular atrophy type I segregating in the same family.

We report on a family with two severe neuromuscular diseases: Duchenne muscular dystrophy (DMD) and acute infantile spinal muscular atrophy (SMA I). One boy has DMD, and his brother died of SMA I at 11 months of age. Both boys had received the same DMD allele from their mother. Analysis of dystrophin by immunohistochemistry and Western blot showed complete lack of dystrophin in both brothers. The mother had a partial deficiency of dystrophin. The boy with SMA I had increased levels of creatine kinase in serum, compatible with DMD, but the muscle biopsy and post-mortem examination of the spinal cord showed the typical changes of SMA I. There were no cytogenetic abnormalities explaining the occurrence of both DMD and SMA I in this family. Molecular genetic prenatal diagnosis of DMD and SMA I, using analysis of RFLPs and dinucleotide repeats, has been performed in one foetus in the family. The results showed that the foetus had a high risk of developing SMA I. An abortion was planned but the pregnancy was terminated by miscarriage.

Adolescent↗

PubMed1994

Inclusion body myositis: clinical, morphological, physiological and laboratory findings in 18 cases.

Eighteen consecutive patients with inclusion body myositis (IBM) were studied. The mean age of onset of symptoms was 60 years. A typical clinical pattern with insidious onset of muscle weakness in knee extensors and finger flexors combined with dysphagia was observed. Serial measurements of the maximal voluntary muscle strength revealed a mean loss of muscle strength of 1.4% per month. Two of the cases had common variable immunodeficiency, and three cases had reduced levels of the IgG3 subclass. Treatment with prednisone resulted in a temporary improvement of muscle function in three patients. No positive effect of azathioprine or cyclosporine A could be documented. The results show that IBM may be associated with immunodeficiency, and that prednisone treatment may temporarily improve the clinical signs. The results from our studies on the progression of the muscle weakness may provide basis for future studies on treatment of IBM.

Adrenal Cortex Hormones↗

PubMed1994

Dilated cardiomyopathy and the dystrophin gene: an illustrated review.

Cardiomyopathy is often found in patients with Duchenne and Becker muscular dystrophy, which are X linked muscle diseases caused by mutations in the dystrophin gene. Dystrophin defects present in many different ways and cases of mild Becker muscular dystrophy have been described in which cardiomyopathy was severe. Female carriers of Duchenne muscular dystrophy can develop symptomatic skeletal myopathy alone or combined with dilated cardiomyopathy. They can also develop dilated cardiomyopathy alone. X linked dilated cardiomyopathy has been found in association with dystrophin defects. The relation between the molecular defects and the cardiac phenotypes has not yet been established. New mutations in the dystrophin gene are common and such mutations cause one third of the cases with Duchenne and Becker muscular dystrophy. This means that sporadic cases of cardiomyopathy caused by dystrophin defects are likely. This paper reports such a case in a boy of 14 who died of dilated cardiomyopathy. Before the cardiac investigation, which was performed one month before he died, he had not complained of muscular weakness. He had minor signs of limb girdle myopathy and slightly increased concentrations of serum creatine kinase. He was found to have an unusual deletion in the dystrophin gene.

Adolescent↗

PubMed1993

Mitochondrial DNA deletions in inclusion body myositis.

Skeletal muscle specimens from three patients with inclusion body myositis, aged 39, 60 and 71 years, respectively, were investigated. Enzyme histochemical staining of cytochrome c oxidase (COX), succinate dehydrogenase and myofibrillar ATPase, and in situ hybridization of transcripts of mitochondrial DNA (mtDNA) were performed on consecutive sections. In all three cases a proportion of muscle fibres (2-5%) showed low or absent COX activity in spite of medium or high succinate dehydrogenase activity (COX deficient muscle fibres). Two probes detecting transcripts of different segments of mtDNA were used for the in situ hybridization. One of the probes (ND4 probe) detected transcripts of a segment of the NADH dehydrogenase subunit 4 gene, which is known to be affected in most cases of mitochondrial myopathy with large deletions of mtDNA. There was reduced hybridization of the ND4 probe in many COX deficient muscle fibres compared with adjacent normal fibres. The other probe (ND2 probe) detected transcripts of a segment of the NADH dehydrogenase subunit 2 gene, which usually is not included in mtDNA deletions. There was accumulation of transcripts corresponding to the ND2 probe in COX deficient fibres in all three cases. These findings demonstrate that deleted mtDNA had accumulated in COX deficient muscle fibres in patients with inclusion body myositis. Southern blot analysis of mtDNA in muscle revealed a 16.6 kb fragment corresponding to normal mtDNA in all three cases. In one case two additional less abundant fragments of smaller size, corresponding to deleted mtDNA, were detected. Ultrastructural investigation showed abnormal mitochondria in all three cases. Control muscle specimens were obtained from nine patients, aged 63-71 years, with muscle pain but without morphological evidence of muscle disease. Occasional COX deficient fibres (< 1%) were found in three of the control cases. The other six control cases showed no COX deficient fibres. Our results show that mtDNA deletions may be involved in the pathogenesis of inclusion body myositis and cause respiratory chain dysfunction in muscle fibre segments.

Adult↗

PubMed1993

Multiple symmetric lipomas with high levels of mtDNA with the tRNA(Lys) A-->G(8344) mutation as the only manifestation of disease in a carrier of myoclonus epilepsy and ragged-red fibers (MERRF) syndrome.

We have investigated the morphology, cytogenetics, and the fraction of mtDNA with the tRNA(Lys) A-->G(8344) mutation in three lipomas in a carrier of this mutation. The son of the patient had myoclonus epilepsy and ragged-red fibers syndrome. The fraction of mtDNA with the tRNA(Lys) mutation varied between 62% and 80% in cultured skin fibroblasts, lymphocytes, normal adipose tissue, and muscle. In the three lipomas the mean fraction of mutated mtDNA was 90%, 94%, and 94%. Ultrastructural examination of the lipomas revealed numerous mitochondria with changes such as electron-dense inclusions in some adipocytes. When considered cytogenetically, the lipomas were characterized by a mixture of karyotypically abnormal and normal cells. An identical del(6)(q24) was found in two tumors. The fraction of mutated mtDNA in cultured lipoma cells was the same as in the lipoma in situ, indicating that the cultured cells were representative of the primary tumor. These findings indicate that the lipomas have originated with a grossly normal stem line and subsequently have developed the 6q deletion. We conclude that the lipomas represent clonal growth of adipocytes with a high content of mtDNA with the tRNA(Lys) mutation. The tRNA(Lys) mutation may be either the direct or the indirect cause of pertubation of the maturation process of the adipocytes, leading to an increased risk of lipoma formation.

Adenine↗

PubMed1992

Mitochondrial DNA deletions and cytochrome c oxidase deficiency in muscle fibres.

We have studied cytochrome c oxidase (COX) deficient muscle fibre segments in 6 patients with mitochondrial myopathy and deletions of mitochondrial DNA (mtDNA). The distribution of transcripts of normal and mutated mtDNA in skeletal muscle sections was studied by in situ hybridization. The results were compared with the enzyme histochemical activity of COX and the immunohistochemical distribution of mtDNA encoded and nuclear DNA encoded subunits of COX. In all cases a proportion of the muscle fibres (less than 1-30% of the fibres in cross-sections) had low COX activity and high activity of succinate dehydrogenase (COX deficient muscle fibres). Transcripts of normal and deleted mtDNA showed the same distribution within the tissue as the corresponding mtDNA, indicating that the deleted mtDNA is transcribed. The COX deficient muscle fibres showed accumulation of transcripts of deleted mtDNA, which had a similar distribution as the accumulated mitochondria within these fibres. With few exceptions, there was a low level of transcripts of normal mtDNA in these COX deficient fibres. Immunohistochemical analysis revealed low levels of immunoreactive material using antiserum to the mtDNA encoded subunits II/III as well as the nuclear DNA encoded subunit IV of COX in all COX deficient muscle fibres. The fraction of deleted mtDNA in muscle ranged from 43 to 87%. There was no correlation between the proportion of COX deficient muscle fibres and the fraction of deleted mtDNA. In 2 cases the deletion did not involve any COX gene. One of these cases had 87% deleted mtDNA but less than 1% COX deficient muscle fibres.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1992

Mitochondrial ATP-synthase deficiency in a child with 3-methylglutaconic aciduria.

We report the finding of mitochondrial ATP-synthase deficiency in a child with persistent 3-methylglutaconic aciduria. The child presented in the neonatal period with severe lactic acidosis, which was controlled by Na-HCO3 and glucose infusions. During the 1st y of life, there were several episodes of lactic acidosis precipitated by infections or prolonged intervals between meals. The excretion of lactate in urine was variable, but there was a persistent high excretion of 3-methylglutaconic acid. The activity of 3-methylglutaconyl-CoA hydratase in fibroblasts was normal. The child had a hypertrophic cardiomyopathy and magnetic resonance images revealed hypoplasia of corpus callosum. The gross motor and mental development was retarded, but there were no other neurologic signs. Investigation of muscle mitochondrial function at 1 y of age revealed a severe mitochondrial ATP-synthase deficiency (oligomycin-sensitive, dinitrophenol-stimulated Mg2+ ATPase activity: 27 nmol x min-1 x (mg protein)-1, control range 223-673 nmol x min-1 x (mg protein)-1. The mitochondrial respiratory rate was low and tightly coupled. The respiratory rate was normalized by the addition of an uncoupler. Low Mg2+ ATPase activity was also demonstrated by histochemical methods. Morphologic examination revealed ultrastructural abnormalities of mitochondria. There was no deletion of mitochondrial DNA. The sequences of the ATP synthase subunit genes of mitochondrial DNA were in accordance with published normal sequences.

Acidosis, Lactic↗

PubMed1992

Activation of insulin-like growth factor II expression during skeletal muscle regeneration in the rat: correlation with myotube formation.

Insulin-like growth factors (IGFs) are important stimulators of proliferation and differentiation of cultured myoblasts. It has previously been shown that IGF-I is induced during muscle regeneration in rodents, however, little is known about the expression of IGF-II. Therefore, two in vivo models were used to analyze IGF-II mRNA expression during skeletal muscle regeneration in the rat: injection of the snake venom notexin and induction of ischemia. During the regeneration process the levels of both IGF-I and IGF-II mRNA were transiently induced, as analyzed by solution hybridization. Both IGF-I-like immunoreactivity and IGF-II-like immunoreactivity were found to be present during muscle regeneration. In a time course study, induction of IGF-II was preceded by IGF-I, both at the mRNA and protein levels. Using alpha- and beta-actin as markers for different stages of skeletal muscle differentiation, together with the immunohistochemistry data, it is concluded that the expression of IGF-I and IGF-II occurs at different differentiation stages, and that IGF-II appears concomitant to the formation of myotubes. These results suggest that each IGF has a distinct role during the differentiation of muscle cells.

Animals↗